so here, proximity is expressed through a variety of words. i don't know if these are all acceptable or not, but if poka is to be the only acceptable preposition for expressing proximity, then it's not a stretch to say tenpo kama poka for near future.

'mi poka sina' doesn't mean "I am at your side" (that is 'mi lon pona sina'); it just means "I am with you", which seems to include just writing check for your campaign, so not necessary physical proximity at all. The extension to feet and so on is not justified. Nor does this justify extending 'pona' to time. On the other hand, 'pona' as an adjective does mean "near" and that might be the basis of an extension to time. However, so far, time issues have been handled with 'kama' and 'pini' and 'mute' and 'sully', that is, non spatially. These may prove inadequate at some point, but we have done so little serious research into what is need and what we have that it is not clear whether we need a new approach or not. To be sure, the number of plausible permutations of the basic elements seems less that the likely needed forms, but let's start with a lay out of all that is taken care of and all that seems needed and works from there. your very brief sketch seems in the right spirit, if not perhaps the right items yet.

English really messes with "with". Other languages do, too, in various ways. I suspect toki pona will develop some odd uses eventually. But for now, 'poka' is only slightly obscure: accompanying actually or being in an active support group, though that is already starting to fuzz at the edges.

When Toki Pona distinguishes between, say, "jelo", "loje" and "laso", I'd rather stick to that distinction. For example, I wouldn't use "jelo" instead of "laso".

This being said, similarly, when Toki Pona distinguishes between "poka", "monsi" and "sinpin", I wouldn't use "poka" instead of "monsi" or "sinpin". Since "poka" primarily means "side", it means "lateral" as a modifier, in contrast to the modifiers "monsi" ("back") and "sinpin" ("front"). And, since time comes and goes, it is more likely for me to perceive time as something "monsi"/"sinpin", but not "poka". (A "lateral" time sounds like sci-fi to me, like a tangent universe with its own timeline next to ours.) This is why I wouldn't use "poka" for time.

I wouldn't use "sinpin" (or "monsi") either, though, because when using "tenpo sinpin", I wouldn't be sure if we're talking about time in front of me or if the time is facing me. (This wouldn't have mattered with "poka".)

A better alternative is using "kama" and "pini" as in "tenpo suno kama" (tomorrow) and "tenpo suno pini" (yesterday). When "kama"/"pini" is used it would be safe to use "poka" in the sense of "near", because "kama"/"pini" already puts the time in prospective: it isn't accompanying, but ahead or behind, but "near".

Thanks. That all seems quite reasonable -- including noting that some notions get muddled together at the moment. I am not quite sure how to interpret 'pini pi tenpo lili' literally, but it seems a pattern which has not been well explored yet and we will need several as this quest continues.(I suppose it means "at the end of a little time" but that is open to several interpretations, too.)